Mechanism and Machine Theory最新文献_第2页

Advantages of elliptical tip vanes on the kinematic design of balanced vane pumps

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-01-03 DOI: 10.1016/j.mechmachtheory.2024.105901

Caterina Natali, Mattia Battarra, Enrico Proner, Emiliano Mucchi

引用次数: 0

A new reciprocating straight propulsion for high propulsive hydrodynamic efficiency 一种新型往复直推进装置，具有较高的推进水动力效率

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-12-03 DOI: 10.1016/j.mechmachtheory.2024.105833

Zhibin Song , Yuanhao Zhang , Yifan Wu , Shiyu Li , Lixuan Zhao , Hongyu Cao , Rongjie Kang , Liwei Shi , Jian S. Dai

{"title":"A new reciprocating straight propulsion for high propulsive hydrodynamic efficiency","authors":"Zhibin Song , Yuanhao Zhang , Yifan Wu , Shiyu Li , Lixuan Zhao , Hongyu Cao , Rongjie Kang , Liwei Shi , Jian S. Dai","doi":"10.1016/j.mechmachtheory.2024.105833","DOIUrl":"10.1016/j.mechmachtheory.2024.105833","url":null,"abstract":"<div><div>The majority of underwater vehicles currently use screw propellers as propulsion method. Despite screw propellers are being promoted to increase the efficiency through better designs and technologies, the circumferential flow caused by the rotation of screw propeller results in wasted energy. This paper proposes an ideal reciprocating straight propulsion paradigm that eliminates this waste by implementing straight backward thrust based on a foldable mechanism. This mechanism can implement a maximized propulsion during the propelling stroke and a minimized resistance during recovery by folding and unfolding the mechanism, which can be adjusted passively via the relative motion between the thruster mechanism and water avoiding using sensors and actuations. This principle makes the reciprocating straight propulsion simple and reliable to be achieved in practice. Besides, a modularized propulsion system with four identical independently thrusters based on the proposed mechanism was proposed, achieving various motion modes in underwater vehicles. The proposed propulsion mechanism was theoretically analyzed and verified through simulations and prototype tests. In mooring tests, the thrust provided by the proposed mechanism is similar to the simulation results. The propulsion performance indicator of an underwater vehicle with the proposed propulsor reached 66 %. The mechanism could turn even with one-sided propulsion.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105833"},"PeriodicalIF":4.5,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand and stand-to-sit motions with energy storage and regeneration: A bond graph approach 具有能量储存和再生功能的从坐到站和从站到坐的膝关节辅助外骨骼的运动学和动力学：键合图方法

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-30 DOI: 10.1016/j.mechmachtheory.2024.105866

Vivek Soni, Anand Vaz

{"title":"Kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand and stand-to-sit motions with energy storage and regeneration: A bond graph approach","authors":"Vivek Soni, Anand Vaz","doi":"10.1016/j.mechmachtheory.2024.105866","DOIUrl":"10.1016/j.mechmachtheory.2024.105866","url":null,"abstract":"<div><div>A bond graph model for the kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand (SiTSt) or stand-to-sit (StTSi) motions is presented. The exoskeleton is actuated by a wire rope connected to a lead screw and slider nut assembly driven by an electric motor. An energy storage spring (ESS) is used for energy storage and regeneration. The ESS and wire rope apply opposite forces on the slider nut resulting in switching of contact surfaces. The kinematics of the lead screw and slider nut assembly is discussed and a bond graph model for the same is developed considering switching of contact surfaces and friction. Kinetics equations are derived from the model and verified by free body diagram (FBD) analysis. The efficacy of the developed model is demonstrated through simulations, where the switching and effects of friction are captured elegantly. Further, mechanics of wrapping is discussed considering the friction between the wire rope and the pulley. Finally, the bond graph model of the proposed exoskeleton is developed. Simulations are carried out by varying the stiffness of ESS and friction coefficients. A reduction in the assistance motor torque, power and energy requirements due to ESS and wrapping is demonstrated.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105866"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A model to study the effect of micropitting on the dynamic behaviour of a geared system 研究微点蚀对齿轮传动系统动态特性影响的模型

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-30 DOI: 10.1016/j.mechmachtheory.2024.105854

S. Portron, Pedro M.T. Marques

{"title":"A model to study the effect of micropitting on the dynamic behaviour of a geared system","authors":"S. Portron, Pedro M.T. Marques","doi":"10.1016/j.mechmachtheory.2024.105854","DOIUrl":"10.1016/j.mechmachtheory.2024.105854","url":null,"abstract":"<div><div>Geared transmission systems operate under increasingly severe conditions that tend to promote micropitting on the gear flanks. Micropitting leads to an increased local coefficient of friction, in particular due to an increase in the average roughness of the damaged surfaces. Micropitting is hard to predict, but also hard to detect, since it mainly affects the contact conditions, which affect friction forces. On global signals such as input/output torque, these friction forces are one to two orders of magnitude lower than the normal forces and tend not to be detectable due to the noise in the experimental setup. This paper aims at studying the effect of micropitting on the vibrational levels of a geared system, by coupling the gear dynamics model developed by Osman and Velex with the roughness-dependent coefficient of friction formulation from Xu et al., and by representing micropitting by a local increase of the composite roughness. The simulations show that micropitting has a clear impact on the system dynamic behaviour, especially in the direction perpendicular to the plane of contact. Finally, it was shown that the bearing forces and the pinion acceleration are suitable candidates for micropitting detection, even with noisy signals.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105854"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On constraint manifolds of planar and spherical mechanisms in Lorentzian space 洛伦兹空间中平面和球面机构的约束流形

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-28 DOI: 10.1016/j.mechmachtheory.2024.105858

Buşra Aktaş

引用次数: 0

Order-of-magnitude increased range of constant force adjustment via section optimization 通过截面优化，恒力调节范围增加了一个数量级

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-27 DOI: 10.1016/j.mechmachtheory.2024.105835

Zeeshan Qaiser , Shane Johnson , Tanzeel ur Rehman , Bi Shun , Ying Zhou

{"title":"Order-of-magnitude increased range of constant force adjustment via section optimization","authors":"Zeeshan Qaiser , Shane Johnson , Tanzeel ur Rehman , Bi Shun , Ying Zhou","doi":"10.1016/j.mechmachtheory.2024.105835","DOIUrl":"10.1016/j.mechmachtheory.2024.105835","url":null,"abstract":"<div><div>An adjustable constant force environment is critical in engineering applications, including precision manipulation, surgical robots, and advanced manufacturing, all requiring a wider range of force regulation and adjustment. Traditional adjustable constant force mechanisms (ACFMs) have significant limitations in achieving a wide range of constant force (CF) adjustments due to factors like stress and interference. Existing ACFMs typically offer only a 2–4 times change in CF, which is insufficient. This research aims to provide an order-of-magnitude increase in CF adjustment range while remaining compact and preserving CF quality through section optimization. An analytical model demonstrates the efficacy of adjusting CF by an order-of-magnitude in prismatic and non-prismatic beams for CF adjustment method selection. Additionally, finite element analysis and design optimization of the non-prismatic serpentine beam with an out-of-plumbness imperfection angle and polynomial section description were conducted to maximize CF adjustability and quality. Experimental validation showed a 38 times change in CF adjustability for 5 percent variation in the CF, 18 times improvement in compactness, and high Energy Similarity Index <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>C</mi><mi>F</mi></mrow></msub></math></span> compared to the prismatic benchmark mechanism. This proposed system may be implemented in several applications, including load control, impact and vibration mitigation, space exercise, wearables, etc.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105835"},"PeriodicalIF":4.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and analysis of an origami-inspired redundant rigid-flexible coupling deployable manipulator 受折纸启发的冗余刚柔耦合可展开机械手的设计与分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-26 DOI: 10.1016/j.mechmachtheory.2024.105852

Ziqiang Zhang , Tianyu Kang , Wenjun Yan , Zhenyun Shi , Zhi Wang , Ye Lu

{"title":"Design and analysis of an origami-inspired redundant rigid-flexible coupling deployable manipulator","authors":"Ziqiang Zhang , Tianyu Kang , Wenjun Yan , Zhenyun Shi , Zhi Wang , Ye Lu","doi":"10.1016/j.mechmachtheory.2024.105852","DOIUrl":"10.1016/j.mechmachtheory.2024.105852","url":null,"abstract":"<div><div>Most manipulators require extensive operational space; however, in environments where space is limited, these devices must be compact during periods of inactivity. To address this challenge, a redundant rigid-flexible coupling deployable manipulator has been developed that optimizes space utilization and enhances operational capabilities. This development is informed by a detailed examination of the structure and motion performance of the Kresling origami unit. Equivalence principles for the mechanism are proposed, and an optimal rigid-flexible coupling equivalent mechanism unit is selected by integrating motion feasibility analysis with the significance of flexible structures. A 3RUU mechanism unit is chosen, and six such units are serially connected to construct a deployable manipulator. The workspace and mechanical properties of the manipulator are characterized, and principles for implementing reach-point motion are proposed to ensure superior overall performance. Experimental results show that the designed manipulator achieves a folding ratio of 2.58, supports a maximum load of 2611.1 g, and exhibits high flexibility and excellent overall performance in reach-point motion. These findings provide a solid foundation for the broader application of this type of manipulator.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105852"},"PeriodicalIF":4.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and analysis of a novel octopod platform with spatial 8R reconfigurable trunk 具有空间 8R 可重构躯干的新型八足平台的设计与分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-26 DOI: 10.1016/j.mechmachtheory.2024.105859

Hui Yang, Hong Liu, Liang Zeng, Jianxu Wu, Yan-an Yao

引用次数: 0

Enhancing anti-disturbance performance of redundant cable-driven parallel robots: Analysis and tension distribution method 提高冗余缆索驱动并联机器人的抗干扰性能：分析和张力分配方法

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-26 DOI: 10.1016/j.mechmachtheory.2024.105861

Jinhao Duan , Hanqing Liu , Le Yan , Zhufeng Shao , Zhaokun Zhang , Xiaoqiang Tang , Minjian Huang , Zixiang Peng

{"title":"Enhancing anti-disturbance performance of redundant cable-driven parallel robots: Analysis and tension distribution method","authors":"Jinhao Duan , Hanqing Liu , Le Yan , Zhufeng Shao , Zhaokun Zhang , Xiaoqiang Tang , Minjian Huang , Zixiang Peng","doi":"10.1016/j.mechmachtheory.2024.105861","DOIUrl":"10.1016/j.mechmachtheory.2024.105861","url":null,"abstract":"<div><div>Anti-disturbance performance reflects the core performance of cable-driven parallel robots (CDPRs) to resist external wrenches and exert wrenches to the outside world, which plays a significant role in the design and control of CDPRs. However, existing analysis methods encounter the issue of dimensional collapse when analyzing the anti-disturbance performance of redundant CDPRs, thereby failing to reflect the influence of tension distribution. In this paper, the augmented wrench space and Augmented Available Wrench Set (AAWS) are proposed for the analysis and tension distribution of redundant CDPRs, establishing the complete mapping between cable tensions and terminal wrenches of redundant CDPRs. The AAWS resolves the issue of dimensional collapse encountered in existing methods, and clarifies the comprehensive impact of tension distribution on the performance of redundant CDPRs. A tension distribution method is developed based on the AAWS to enhance the anti-disturbance performance of redundant CDPRs. Simulation indicates that the proposed AAWS-based tension distribution method effectively improves the anti-disturbance performance compared to the commonly used 2-norm-based method and the centroid method. This paper presents an efficient and universal approach for analyzing, evaluating, and improving the anti-disturbance performance of redundant CDPRs.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105861"},"PeriodicalIF":4.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the behaviour of n-planets planetary gear sets influenced by geometrical design factors 关于受几何设计因素影响的 n 行星行星齿轮组的行为

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-25 DOI: 10.1016/j.mechmachtheory.2024.105860

J. Sanchez-Espiga , M. Fuerst , A. Fernandez-del-Rincon , M. Otto , F. Viadero , K. Stahl

{"title":"On the behaviour of n-planets planetary gear sets influenced by geometrical design factors","authors":"J. Sanchez-Espiga , M. Fuerst , A. Fernandez-del-Rincon , M. Otto , F. Viadero , K. Stahl","doi":"10.1016/j.mechmachtheory.2024.105860","DOIUrl":"10.1016/j.mechmachtheory.2024.105860","url":null,"abstract":"<div><div>This work presents a study focused on the behaviour of low-speed planetary gear sets with 3 to 7 equally spaced planets affected by their inherent geometrical characteristics. On the one hand, this work identifies the conditions that make the transmission act as fixed, even including floatability in the sun gear, due to their inherent geometrical factors in transmissions with an even number of planets. On the other hand, this work extends the criteria employed to classify the kinds of planetary gearboxes according to their geometry, including the order of the sequence in a sequentially phased transmission. A new expression is proposed in order to take this order into account. Then, several different transmissions are modelled covering the possible configurations. To observe the impact that these aspects have in the transmission’s behaviour the load sharing ratio and the orbits described by the sun gear are extracted. These results confirm the importance of the mentioned sequence order in the behaviour of these transmissions.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105860"},"PeriodicalIF":4.5,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0